Charlize Theron and Sean Penn's romance 'blossomed' from friendship

Fresh speculation about the nature of their relationship has now begun after the actress and her two-year-old son Jackson jetted to Hawaii to stay with Sean over New Year. (Photo by J. Vespa/WireImage)The two stars are known to be good friends and were romantically linked when Charlize split from her long-term boyfriend Stuart Townsend in 2010. (Photo by Frank Micelotta/Getty Images)

Charlize Theron and Sean Penn's supposed romance has blossomed after they were friends "for years".

The two stars are known to be good friends and were romantically linked when Charlize split from her long-term boyfriend Stuart Townsend in 2010.

Fresh speculation about the nature of their relationship has now begun after the actress and her two-year-old son Jackson jetted to Hawaii to stay with Sean over New Year.

"Charlize and Sean have been friends for years," an insider told People magazine. "They have been spotted out together several times in the past few years. Even when Charlize was dating Stuart. They both had dinner with Sean several times."

The publication claims the group stayed at the 53-year-old actor's beachfront home in Oahu. Sean was seen surfing during the afternoon of December 31, while Charlize showed off her svelte figure in a stripy bikini.

The following day they returned to Los Angeles on the same flight and they were seen leaving the blonde actress' home in separate vehicles yesterday.

In October, Charlize and Sean set tongues wagging when they were spotted looking close at a Halloween party thrown by Seth MacFarlane.

News of the alleged romance comes as a surprise, as before the holidays Sean was widely thought to be rekindling his romance with his ex-wife Madonna following her split from Brahim Zaibat.

The former couple were seen holding hands during a humanitarian trip to Haiti and it was suggested their relationship was going from strength to strength.

"They’re in touch non-stop. Friends are joking they’ll be remarried by this time next year," a source told British newspaper The Sun.